#3F66A9
Closest named color: French Blue (#436BAD). oklch(51.4% 0.116 260.6), rgb(63, 102, 169).
Aa
White text reads best on this color (5.69:1).
About this color
#3F66A9 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 51%, its chroma 0.116 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is French Blue (#436BAD), ΔE 0.016 away. White text reads best on it, at 5.69:1.
| Hue family | Blues |
| Lightness | medium-dark (51%) |
| Chroma | moderately saturated (0.116) |
| Temperature | cool |
| Nearest name | French Blue (#436BAD) |
| Black text | 3.68:1 |
| White text | 5.69:1 |
Values
| HEX | #3F66A9 |
| RGB | rgb(63, 102, 169) |
| HSL | hsl(218, 46%, 45%) |
| OKLCH | oklch(51.4% 0.116 260.6) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #3F66A9 | 5.69:1 | AA | Lc -83.6 | Fine for body text |
| Black text on #3F66A9 | 3.68:1 | AA large text | Lc 25.8 | Dividers and decoration only |
| #3F66A9 text on white | 5.69:1 | AA | Lc 78.3 | Fine for body text |
| #3F66A9 text on black | 3.68:1 | AA large text | Lc -23.5 | Dividers and decoration only |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 700.
-
Step 50
50
#F3F6FB
oklch(97.2% 0.007 260.7)
-
Step 100
100
#E4EAF5
oklch(93.6% 0.016 262.8)
-
Step 200
200
#CEDAEE
oklch(88.5% 0.03 260.7)
-
Step 300
300
#ACC2E5
oklch(80.9% 0.055 259.6)
-
Step 400
400
#80A1D9
oklch(70.6% 0.09 260.7)
-
Step 500
500
#6189CE
oklch(63.1% 0.114 260.8)
-
Step 600
600
#4772BB
oklch(55.6% 0.124 260.4)
-
Step 700
700 (this color)
#3F66A9
oklch(51.4% 0.116 260.6)
-
Step 800
800
#2F4E83
oklch(42.7% 0.096 260.5)
-
Step 900
900
#2A4169
oklch(37.7% 0.075 260.9)
-
Step 950
950
#19263D
oklch(26.9% 0.047 261.3)
#3F66A9 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #496CAC | 0.022 |
| Deuteranopia (no green cones) | #3A62A8 | 0.013 |
| Tritanopia (no blue cones) | #00757F | 0.098 |
| Achromatopsia (no color) | #666666 | 0.116 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F66A9
#3F66A9
oklch(51.4% 0.116 260.6)
- #875F00
#875F00
oklch(51.4% 0.107 79.9)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #3F66A9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- French Blue #436BAD ΔE 0.016
- Mid Blue #276AB3 ΔE 0.024
- Dusky Blue #475F94 ΔE 0.035
- Flat Blue #3C73A8 ΔE 0.038
- Muted Blue #3B719F ΔE 0.039
- Denim Blue #3B5B92 ΔE 0.045
- Denim #3B638C ΔE 0.047
- Ocean Blue #03719C ΔE 0.052
Use #3F66A9 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.